The issue with size changing, primarily (but not exclusively) a fairy thing, can be a bit confusing even though it is really straightforward, so I figured I'd explain it a bit.
Changing one's size is an ability strongly related to one's magic reserves. It has never been known to be an ability available to psychics, only mages, namely fairies.
Male fairies with red soul auras (the ones you'd better avoid) can grow/shrink their prey. All female fairies, blue or red soul auras, can size change their prey. A human sized fairy can shrink a giant down to bite size or a bite size person to giant sized
if she has enough magic reserves. It is in fact fatal for a fairy to make a human a giant because the human's organs will fairly quickly fail. Making another fairy...
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